Conventional shock absorbers are metal springs, friction buffers, hydraulic buffers, rubber moldings, and combinations thereof. Metal springs show superior buffering performance but scarcely absorb energy. Friction buffers and hydraulic buffers generally have complicated structure and are expensive, as well as pose problems in terms of very high deformation rate-dependency and poor restorability. In addition, these buffers are restrictive of installation environment, since they are associated with difficulties in using in water and require maintenance against rust and water. Rubber moldings show high restorability, whereas suffer from low modulus of elasticity possessed by the constituent material. To achieve satisfactory shock absorption, therefore, the rubber moldings need to contain large amounts of rubbers to the extent that the resultant heavy weight of the rubber prevents realization of large-sized rubber moldings. While these conventional shock absorbers can be used beneficially for buffering a compression load applied over a small area, they are not suitable for the structures requiring a uniform cushion characteristic over a wide area, such as side walls of roads, and floors and walls of buildings.
In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a resin shock absorber having a light weight, a simple structure, a high energy absorption efficiency for its reaction force, and superior restorability, which is maintenance-free as a result of its resistance against rust, water and weather, permitting its use both above the ground and in the sea; is extendably assembled as required; and is capable of achieving a uniform cushion characteristic over a wide area.